Roller bender for offset printing plates

ABSTRACT

A bending machine for offset printing plates. The bender includes a table support for the plate to be bent. The table is provided with end edges having contours identical to the desired contours of the end edges of the plate after bending. Spring biased rollers are employed to bend the end edges of the plate around the contoured ends of the table support.

Unite States Patent [191 Gregoire [54] ROLLER BENDER FOR OFFSET PRINTINGPLATES [76] Inventor: Clyde G. Gregoire, 4N194 Briar Ln., Bensenville,Ill. 60106 [22] Filed: July 15, 1971 [21] Appl. No.: 162,988

[52] U.S. Cl. ..72/213 [51] Int. Cl. ..B21d 9/08 [58] Field of Search..72/210, 212, 213, 72/320, 321, 401, 215

[5 6] References Cited UNITED STATES PATENTS 1,877,110 9/1932 Wunderlich..72/212 [111 3,733,872 1 May 22, 1973 2,343,082 2/1944 Proctor ..72/213X 2,932,337 4/1960 Benedict et a1 ..72/213 2,420,119 5/1947 Boehm et a]...72/212 Primary Examiner-Milton S. Mehr Attorney-Snow and Benno 57ABSTRACT A bending machine for offset printing plates. The benderincludes a table support for the plate to be bent. The table is providedwith end edges having contours identical to the desired contours of theend edges of the plate after bending. Spring biased rollers are employedto bend the end edges of the plate around the contoured ends of thetable support.

6 Claims, 9 Drawing Figures PATENTELWQM 3.733.872

SHEET 1 [1F 4 PATENTELELZYQ? m5 SHEET U [1F 4 Hllll ROLLER BENDER FOROFFSET PRINTING PLATES BACKGROUND OF THE INVENTION 1. Field of theInvention The offset printing industry uses thin plates, usually ofaluminum or other metal or metal alloy, onto which an image to beprinted is deposited by photographic processes. When the plates aresubsequently used in a printing press it is desirable to accuratelyposition the plate so that the printed image is properly centered on theprinted page. The necessity for proper positioning of the plateimmeasurably increases when multiple colors are used and two or moreplates are impressed on the same printed page. It is obvious thatwithout such accurate positioning there would be improper colorregistration.

The plates are ordinarily wrapped around cylinders in presses while theyare used to effect an imprinting. As a rule the plates are held on thecylinder by clamping means engaging the end edges of the plate. Thisclamping is facilitated by the bending of the end edges at somepredetermined position and in some predetermined contour orconfiguration which complements a receiving contour in the surface ofthe mounting cylinder. Exact and accurate bending of the plates is thusof the utmost importance in obtaining a good printing job.

2. Description of the Prior Art There have been many attempts to providemechanized bending of the ends of offset printing plates but to ourknowledge all have been more or less failures. Most bending done todayis by manual means which is slow and tedious and not always as accurateas desired. The printers of daily newspapers of any size have the taskof bending the ends of plates for each page. Also, with advertisingrevenues at present rates it would be unthinkable for a publisher toskip one page of this paper with advertising content because of a faultyplate. This means that not only must the printer bend the ends of aplate for each page but also must bend the ends of a back up plate orplates for each page.

SUMMARY OF THE INVENTION The present invention relates to a new andimproved bender for the ends of offset printing plates known generallyas semi-cylindrical or wraparound.

An important object of this invention is to provide novel rolling meansfor causing the bending of the ends of offset printing plates around thecontoured ends of a plate supporting table.

Another important object of this invention is to provide novel means formounting the bending rolling means to follow the contoured end edges ofthe plate supporting table.

Another important object of this invention is to provide a novel meansfor bending the end edges of an offset printing plate by moving a platesupporting table past yieldably mounted bending rollers.

Still another important object of this invention is to provide hingedarm means for carrying the yieldably mounted bending rollers and meansfor normally spring urging the arms in such a manner that the rollersare moved inwardly against the ends of the plate to be bent.

Another important object of this invention is the provision of a deviceas set forth in the preceding object in which all accumulations ofpossible errors in the exact size bending of plates are nullified due tothe inward or central biasing of the rollers.

A still further important object of this invention is to provide a novelsupporting table for an offset printing plate to be bent and includingan extensible and retractable end edge to facilitate adjustable spacingof the end edges and easy removal of the plate after bending.

A still further important object of this invention is to provide a novelbender for the ends of wrap-around offset printing plates which includesa vacuum table to prevent the plate from moving during the bendingcycle.

Other and further important objects and advantages will become apparentfrom the disclosures in the following specification and accompanyingdrawings.

IN THE DRAWINGS FIG. 1 is a perspective view of the exterior of theplate bending machine of this invention.

FIG. 2 is a view similar to FIG. 1 with portions of the outer wallsremoved to disclose the interior.

FIG. 3 is a perspective view of an offset printing plate with the endsthereof bent by the device of this invention.

FIG. 4 is a cross sectional view of a printing machine cylinder adaptedto receive an offset printing plate on the surface thereof in a wrappingtherearound.

FIG. 5 is a top plan view of the device of FIGS. 1 and 2.

FIG. 6 is a sectional view taken on the line 6-6 of FIG. 5.

FIG. 7 is a partial view of the device as in FIG. 6 with the one endedge of the table fully extended.

FIG. 8 is another partial view of the device as in FIGS. 6 and 7 withthe plate supporting table moved up to permit the spring biased rollersto engage and bend the ends of the plate to conform to the contour ofthe end edges of the supporting plates.

FIG. 9 is a detail view of a part of the end of the table lift bar astaken on the line 9 9 of FIG. 5.

AS SHOWN IN THE DRAWINGS The reference numeral 10 indicates generallythe offset printing plate bending machine of this invention. The bendingmachine includes a housing or supporting structure having spaced apartend walls 11 and 12, a front wall 13, and a back wall 14. The end wall11 has spaced apart floor engaging legs 15 and similarly the end wall 12has spaced apart floor engaging legs 16. The legs 15 and 16 arevertically adjustable to provide for convenient levelling of the bendingmachine.

As best shown in FIG. 1 an operator 17 is standing at the bendingmachine 10. The top of the machine is about waist high and permits easyinsertion of plates to have their ends bent. Also, removal of the platesafter bending is made easy as will hereafter be described. Therectangular plates used in offset printing machines are made of thinmetal and are wrapped around cylindrical rollers so their shape inprinting use is generally semi-cylindrical. FIG. 3 is an illustration ofan end bent plate 18. The plate comprises a rectangular central portion19, a position registering circular hole 20, a position registeringelongated hole 21, a bent end 22, and a bent end 23. The plates used inthe printing process are prepunched with the registering holes 20 and 21and after the printing matter is deposited on the rectangular surface 19by a photographic process the ends are accurately bent for the purposeof holding the printing plate in a printing cylinder used in printingmachines. FIG. 4 illustrates a printing cylinder 24 onto which the bentend plate 18 is mounted. The cylinder includes a central shaft 25 andarcuately spaced apart undercut notches 26 and 27 in the cylindricalsurface. The notch 26 is adapted to receive the acutely bent end 22while the notch 27 receives and grips the acutely bent end 23. Theinterengagement of the bent ends with the undercut notches in thecylinder act to hold the body of the bent end plate snuggly against thesurface of the cylinder during the printing operation.

As best shown in FIG. 2 a toggle switch 28 acts to energize an electricmotor operated vacuum pump to be subsequently described. The othercontrols of the bending machine include spaced apart dual operatingstarter switches 29 and 30 which insure that the operators hands are outof the way when the machine does its bending. All the control switches28, 29, and 30 are mounted on a top frame member 31. The machine of thisinvention as shown in the disclosed embodiment is sufficiently longbetween the end walls 11 and 12 to accommodate two plates forsimultaneous bending. As shown in FIG. 5 separate, side-by-side tables32 and 32a are provided in the machine to receive two plates forbending. In FIG. 2 table 32 has been removed to show the interior of themachine. A horizontally disposed slot 33 is provided in the end wall 12to conveniently insert plates to be end bent or removed after bending iscompleted.

As best shown in FIG. 6 another top frame member 34 is provided adjacentthe front wall 13. The top frame member 34 is parallel to and spacedapart from the top frame member 31. These two frame members 31 and 34flank the ends of the plate receiving tables 32 and 32a as shown in FIG.5.

The construction of the underside of the tables 32 and 32a is best shownin FIGS. 6, 7, and 8. A base 35 is adapted to carry the table tops 32.An end edge 36 of the table is fixedly mounted on the base 35. On theother side of the base support 35 is a slidably movable section 37.Another opposite end edge 38 of the table is mounted on the movablesection 37. The table end edges 36 and 38 are parallel to each other andboth have contoured or configuration endings 39 and 40 respectively overwhich the plates are to have their ends bent. The end edge 36 isstationary while the end edge 38 is movable in and out to permit easyinsertion of the plate and easy removal of the bent plate.

Spaced apart plate registration pins 41 and 42 are provided to hold theplates to be bent during initial application to the tables. The pin 41is mounted on a stationary rod member 43 forming part of the basicsupporting structure of the bending machine. The rod extends between andis carried on the end walls 11 and 12. The pin 42 is mounted on astationary rod member 44 which is disposed parallel to and spaced apartfrom the rod 43. The rod 44 is also carried in the end walls 11 and 12and spans the space therebetween to form a part of the basic supportingstructure of the bending machine.

Generally vertically disposed spaced apart arms 45 and 46 are pivotallymounted respectively on the end wall 11 at 47 and 48. An adjustable stopmember 49 threadedly engages the arm 45 and is adapted to have its endpass through the arm 45 and abut the stationary rod 43 and thereby limitthe inward swinging movement of the arm 45. Similarly an adjustable stopmemher 50 is threaded into the arm 46 and is adapted to have its endabut the stationary rod 44 and thus limit the inward swinging of the arm46. The normal disposition of the arms is generally vertical. However,during the bending operation the arms may and do swing outwardly. Thearm 45 has a lower portion 51 and similarly the arm 46 has a lowerportion 52. Extension springs 53 and 54 are disposed between the lowerend portions 51 and 52 thus causing the pivoted arms to be urgedoutwardly at their lower ends and inwardly at their upper ends. Acentral stationary support 55 is arranged and constructed to receive theinner ends of the extension springs 53 and 54. The upper ends of thearms 45 and 46 are identified respectively by the numerals 56 and 57.

A plate bending roller 58 has its one end journaled in the upper end 56of the swingable arm 45. Another arm 45a, identical to the arm 45, ismounted for pivoting support on the other end wall 12. The other end ofthe roller 58 is journally mounted in the arm 45a. Another plate bendingroller 59 has its one end journaled in the upper end 57 of the swingablearm 46. The other end of the roller 59 is journally carried in an arm460 which is the mate of the arm 46. The arm 46a is pivotally mounted onthe end wall 12. The rollers 58 and 59 thus lie parallel to one anotherand by reason of their mounting on the spring biased arms 45, 45a, 46and 460 they are urged inwardly against the contoured ends 39 and 40 ofthe plate holding tables 32 and 32a. The rollers 58 and 59 have beenshown with smooth cylindrical surfaces. However, if it is desired tohave reverse bends in the plate edges the rollers may be notched toengage cooperatively notched outer edges 36 and 38 of the tablesupporting the plates to be bent.

A bar 60, rectangular in cross section, extends between the arm 45 andthe arm 45a and acts as a stabilizer for the roller 58 and in theholding of the arms 45 and 45a in fixed relationship for movement inunison. An adjustable screw 61 threadedly engages the bar and has itsinner end adapted to abut the back of the bending roller 58 as bestshown in FIG. 6. An L-shaped block 62 is affixed to the top of the bar60 at the center thereof. A portion of the block 62 overhangs the roller58 as shown in both of FIGS. 2 and 6. Another adjustable screw 63 isvertically disposed and threadedly engaged in the block 62 directlyabove the roller 58. The lower end of the screw 63 abuts the top of thebending roller 58. Both adjusting screws 61 and 63 act to prevent theroller from deflecting away from its normal position during the severeload imposed thereon when bending the ends of offset printing plates.With undesired deflection eliminated, uniform bending along the full endof the plate is insured.

A bar 64, also rectangular in cross section, is similar to the bar 60and extends between the arms 46 and 46a and acts as a back-up for theroller 59. Adjustable screw 65 is threaded into and through the bar 64and has its inner end abutting and supporting the roller 59. An L-shapedblock 66 similar to the L-shaped block 62 is mounted on the center ofthe bar 64 and is equipped with a verticaliy disposed threaded adjustingscrew 67 for abutting the top of the roller 59. As in the case of theadjusting screws 61 and 63 the roller abutting screws 65 and 67 preventthe roller 59 from deflecting during the plate bending operation.

The lower end of the housing or supporting structure is provided withreinforcing T-frame members 68 and

1. An end bender for off-set printing plates comprising a table toreceive the plates to be bent, means locating said plates on said table,said table including end edges having contours the same as those desiredfor the ends of the plates after bending, roller means, means arrangedand constructed to cause said roller means to engage said contoured endedges and bend the ends of the plates by a cooperative rolling action ofthe roller means over the contoured end edges of the table, supportingmeans for carrying the table and the roller means, arms pivotallymounted intermediate their ends on said supporting means, said rollermeans having ends thereof journally mounted in the ends of the arms onone side of the pivotal mountings, spring means engaging the other endsof the arms and arranged to urge said roller means against the contouredend edges of the table, and means moving said table past said rollermeans whereby the roller means follows the contours of the end edgescausing the plate to be roll bent therearound.
 2. An end bender for theplates of offset printing plates comprising a supporting structure, atable mounted on said supporting structure, said table adapted toreceive plates to be bent, means locating said plates on said table,said table including end edges having contours the same as those desiredfor the ends of the plates after bending, roller means, means mountingsaid roller means on said supporting structure, spring biasing meansarranged and constructed to cause said roller means to yieldably engagesaid contoured end edges and bend the ends of the plates by acooperative rolling action of the roller means over the contoured endedges of the table said table movable relative to said supportingstructure, and said means for mounting said roller means on thesupporting structure including arms pivotally mounted intermediate theirends on said supporting structure, said roller means journally mountedin the ends of the arms on one side of their pivotal mounting, saidspring biasing means including spring means engaging the other ends ofthe arms and arranged to urge said roller means against the contouredend edges of the table, and means moving said table past said rollermeans whereby the roller means follows the contours of the end edgescausing the plate to be roll bent therearound.
 3. An end bender as setforth in claim 1 in which said table has at least one end edge which ismovable from a retracted position to an extended position, and saidmeans moving said table past said roller means comprises means to firstextend said table end edge.
 4. A device as set forth in claim 3 in whichsaid means for moving said table past said roller means and the means tofirst extend said table end edge comprises a fluid cylinder pivotablymounted at its lower end on said supporting means, said cylinder havingat its other end an extendable piston, toggle linkage associated withsaid extendable piston and said table end edge whereby initial extensionof said piston causes said toggle linkage to extend said end edge, andcollar means on said piston arranged and constructed to engage and movesaid table after said toggle linkage has extended said end edge.
 5. Adevice as set forth in claim 4 in which said toggle linkage is equippedwith a coupling intermediate the ends thereof to adjust the lengththereof by shimming.
 6. An offset printing plate bender comprising asupporting structure, a table arranged to receive a plate to be bent,said table mounted on and capable of movement relative to saidsupporting structure, means moving said table in one direction on saidsupporting structure, said table including spaced apart end edges havingcontours the same as those desired for the ends of the printing plateafter bending, said spaced apart end edges of said table constitutingplate bendIng edges, means spreading at least one of said bending edgesoutwardly prior to moving said table in the said one direction on saidsupporting structure, spaced apart arms pivotally mounted on saidsupporting structure, a roller carried at one end of each of said spacedapart arms, spring means normally urging said rollers inwardly towardsaid spaced apart bending edges of said table, said means moving saidtable in the one direction with its outwardly spread bending edge andplate mounted thereon past said rollers whereby the rollers cause theends of the plate to be bent over the contoured bending edges of thetable, means moving said table in the opposite direction for return toits original position on said supporting structure, and meanssubsequently retracting said outwardly spread bending edge prior toremoval of said printing plate after having its ends bent.